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Biomedical subjects

J Setz

Publications and source records attributed to J Setz.

At least 19 recordsLinked to original sources
PubMed1997

In vivo color stability of resin-veneered telescopic dentures: a double blind pilot study.

STATEMENT OF PROBLEM: Discoloration is a major disadvantage of resin veneers on telescopic dentures. In vitro color measurements with large and flat samples of resin veneer composites have been published, but no in vivo data are available. PURPOSE: This study describes the discoloration of resin veneers in vivo by use of spectrophotometry and the L*a*b* system of the Commission Internationale de L'Eclairage (CIE). METHODS: In a clinical evaluation of this technique, two composite veneer materials were compared in 18 patients. RESULTS: Both brands discolored significantly after 1 year. While L* and a* were not changed significantly, b* and the total color difference delta E increased by approximately 2 units each year. No statistically significant differences were found between the materials.

Color↗
PubMed1996

Disinfection of pumice.

Pumice is a potential source of infection for the dental technician and of cross-contamination between different dentures and patients. In this study, the number of microorganisms in two different combinations of pumice and disinfectant was compared with a conventional mixture of pumice and water. The results revealed that under practical conditions the mix of Steribim (pumice containing benzoic acid added by the manufacturer) with water reduced the number of bacteria by 99% compared with a mix of a conventional pumice and water. The addition of an antiseptic product that contained octenidine as active agent to conventional pumice reduced the number of microorganisms by 99.999%.

Anti-Infective Agents, Local↗
PubMed1994

Gingival reaction on crowns with cast and sintered metal margins: a progressive report.

Sintered metals have been developed recently for the construction of metal ceramic crowns (Degusint U). An unbalanced, randomized double-blind study was conducted to compare the gingival response to artificial crowns with sintered noble metal margins and cast noble metal margins (Degudent U) by measuring the sulcus-fluid-flow rate (SFFR) in highly motivated patients. In a prior study marginal opening of 20 microns were recorded for cast metal crowns, whereas two sintered metal crowns had marginal openings of 40 microns. Three metal ceramic crowns (Renaissance, Degusint U, and Degudent U for the copings and VMK 68 porcelain) with subgingival margins were prepared and fabricated for 12 intact natural teeth. The SFFR was measured for teeth with artificial crowns and adjacent natural teeth after provisional insertion of each crown. Significantly elevated SFFRs were recorded for all artificial crowns compared with the adjacent natural teeth, but there were no variations recorded for the different types of crown margins.

Analysis of Variance↗
PubMed1991

[Disinfection of dental impressions].

The need for disinfection of dental impressions is generally postulated. While many disinfectants for elastomeric impression materials have been recommended for at least ten years, several authors recently described suitable disinfectants for alginate impressions. Disinfectants for reversible hydrocolloid materials are in the phase of practical testing, and show promising first results. Under practical and scientific aspects further investigations are necessary to evaluate standards and standardized testing procedures.

Alginates↗
PubMed1991

[Wettability and accuracy of reproduction of impression materials].

Traditional elastomeric impression materials, four recently developed "hydrophilic" silicones and a hydrocolloid have been tested for their accuracy of reproduction by use of indirect measurements via plaster dies and for their wettability by means of the sessile drop method. The new silicones are reproducing the original model as exactly as the traditional elastomers. The impression techniques have a stronger influence on the results than the impression materials. Although the new silicones are more hydrophilic than the traditional elastomers, they do not reach the wettability of a hydrocolloid. The results of the indirect measurements and the results of the contact angle measurements are corresponding to the results of other investigations and to literature data of bubble counts of plaster dies made of different impression materials.

Dental Impression Materials↗
PubMed1991

[The effect of inorganic fillers on the properties of light-curing composites].

Light curing composite resins became the preferred material in treating carious or traumatic lesions of anterior teeth. Attempts to improve the properties of these materials lead to the development of hybrid composites with an amount of anorganic fillers of more than 80 weight %. It was the purpose of this study to investigate whether composites with higher amounts of anorganic filler show better properties than those with lower amounts of filler. Eight commercial and two experimental composites have been tested for their resistance to abrasion by simulated toothbrushing, polymerization shrinkage, water sorption, porosity, and surface quality. The results showed no correlation between the amount of anorganic filler on the one hand and tested properties on the other. The amount of anorganic filler is no quality criterium per se, the properties of a composite are rather influenced by composition and quality of the organic matrix, even if the amount of anorganic fillers increases to more than 80 weight %.

Composite Resins↗
PubMed1990

[Color stability of light curing composites].

Eight commercial and two experimental light cured composite have been tested for color stability after experimental aging. Color differences were measured by computer-controlled spectrophotometry and expressed in terms of L*A*B* color coordinates (CIELAB). Although three composites with a high content of anorganic filler showed the best color stability and the material with the lowest anorganic filler content showed the greatest discoloration, there was no strong correlation between the amount of anorganic filler on the one hand and color stability after experimental aging on the other.

Color↗
PubMed1990

[Properties of a measuring system for digital occlusion diagnosis].

The properties of a new digital technique of demonstrating and quantifying occlusal contacts (T-scan) were tested in vitro the sensor foil used was 95 microns in thickness and had approx. 1350 measuring points. When a given force was applied at the same point on one foil several times in sequence, the readings were highly reproducible. Applying the same force at different points on the same foil and at points on different foils, however, failed to bring about reproducible results. The reasons for this lack of reproducibility and possible modifications are discussed.

Bite Force↗
PubMed1989

[The antimicrobial effect of an alginate with an antiseptic admixture].

Attempts to simplify impression disinfection lead to the production of an aseptic alginate impression material (Blueprint asept, De Trey/Dentsply, Konstanz, Germany). This study describes the aseptic properties of this new type of impression material. The in-vitro part of the experiments showed a reduction of Staphylococcus aureus by 6 and of Pseudomonas aeruginosa by 4 log steps after 60 min, and of Candida albicans by at least 3 log steps after 15 min of exposure. Under in-vivo conditions oral bacteria residing on the impression surfaces were reduced by nearly 4 log steps. Although the aseptic properties of the material were demonstrated, the biological acceptance, dimensional stability and compatibility with gypsum have to be tested in further studies.

Alginates↗
PubMed1989

[Radiosterilization of impressions].

Dimensional stability and mechanical properties of addition-silicone impression materials were tested after sterilisation with gamma rays. There were no clinically relevant changes to not sterilized materials.

Dental Impression Materials↗
PubMed1989

Complete dentures fixed on dental implants: chewing patterns and implant stress.

Electrognathographic measurements on 18 patients with implant-attached mandibular complete dentures showed larger and more stable chewing patterns compared to their former dentures without implants. Strain gauge measurements revealed mechanical stress acting on the implants even during the fixation of the bar. In addition to simulating the periodontal ligament, the intramobile element (IME) of the IMZ system compensated minor, clinically undetectable mismatches inherent with technical procedures (casting, soldering). Although the implants are loaded with tensile and compressive stress, tensile stress dominated during the chewing process. The implants were also loaded during swallowing. This load reached half of the value of the chewing loads.

Dental Implantation, Endosseous↗
PubMed1989

[Effects of caries-preventive fluoride gels on dental ceramics].

The effects of several fluoride gels on ceramic surfaces (Dicor, Optec, Biodent ceramic and Vita VMK) were tested by SEM and by means of an electrical stylus instrument. After 10 min exposure time an acidulated gel (Oral-B Fluoride-Gel) showed a significant effect, whereas the effect of two non-acidulated gels (Elmex-Gelee, Blend-a-med Fluoride Gel) was not significant. After 24 h exposure time, Elmex and Blend-a-med gel showed an effect, too.

Dental Porcelain↗